Tech.view: Electric cars at the crossroads

Spinning wheels

SEVERAL months ago, your correspondent put his name down for a Nissan Leaf, an all-electric car that the Japanese manufacturer is betting the company on. The vehicle is to be launched in America, Japan and several European countries in December. Its five seats, 100-mile (180km) range and overnight recharging from a domestic electricity supply made it appear, at least to your correspondent, ideal for the school run and the odd foray to the shops. As a zero-emission vehicle, the Leaf would also qualify, even with only one person on board, for the high-occupancy-vehicle lanes on Los Angeles's busy freeways. That can make a huge difference during rush hours.

The chance to appear fashionably green and to have privileged access to car-pool lanes were not the only attractions. Californian tax payers get a $5,000 credit from the state for buying an electric vehicle, and that is on top of a $7,500 incentive from the federal government. Subtract those bribes from the proposed sticker price of $32,780, and a Leaf on the road would cost a little over $20,000. A comparably equipped hybrid like the Toyota Prius would be around $27,000.

Now, however, your correspondent is not so sure that the Leaf is such a bargain. It might be better to pay the premium for a regular hybrid like the Prius, or possibly even a plug-in hybrid such as General Motors's offering (to be known as the Volt in America and the Ampera in Europe), with its range-extending petrol-powered generator under the hood. What has given him pause for thought is BMW's recent trials in America, Germany and Britain of some 500 electric versions of the Mini. The firm has been boasting that the Mini E will get 156 miles between charges. In “real-world” conditions, however, test cars have been averaging around 100 miles, and some drivers have been getting as little as 40 miles in chilly weather.

Admittedly, the modern Mini is a podgy car for its size, weighing in at 2,500lb (1,100kg)—nearly twice as heavy as Sir Alec Issigoniss's original design. Stick 570lb of lithium-ion batteries where the back seat should be, and the Mini E is certainly no bantamweight. But neither is the Leaf, which is expected to tip the scales at over 3,000lb. Factor in the latter's smaller battery capacity (24 kilowatt-hours to the Mini E's 35 kW-h), and the Leaf could be averaging less than 60 miles between charges in normal use.

General Motors thinks that is more than enough for the average American commuter to get to work and back. The Volt has been designed to travel 40 miles on a full charge. After that, the car's generator kicks in to replenish the battery and propel the vehicle. So, even if the Volt gets no more than 25 miles of electric motoring in practice, the driver need not worry about being stranded at the side of the road (provided there is still petrol in the tank). With the Leaf, by contrast, any miscalculation of range means your correspondent risks coming home behind a tow-truck.

The curse of all electric cars is the battery. It was bad enough when they relied on nickel-metal hydride batteries, as the Prius still does. Though safe and reliable, such batteries are big and heavy, and do not store anywhere near enough energy for plug-in vehicles.

The new generation of batteries, based on lithium-ion cells, are lighter and can store far more juice. Unfortunately, they are a good deal pricier and need lots of cooling. Lithium is a reactive, inflammable metal. Unless the temperatures and voltages within individual cells are monitored carefully, lithium-ion batteries can suffer “thermal runaway” and explode—as has happened on numerous occasions with similar batteries used in laptops and mobile phones (see “Less bang for your buck”).

Moreover, supplies of the metal are far from abundant, and are located in countries not necessarily friendly to America: the biggest reserves are in Bolivia, China and Russia. Then, there is the issue of charging a plug-in car overnight. In most places, the electricity delivered during off-peak periods comes from dirty coal-fired power stations—rather negating the point of having a zero-emission vehicle in the first place.

The answer, in your correspondent's view, is to get rid of those pesky battery packs and replace them with flywheels. Buses and trains have experimented with such devices for decades, and huge strides have been made recently in using them to add zip to road cars. For that, thank Formula One motor racing.

Your correspondent has long argued that this sport's relentless demand for the ultimate in lightness and performance—with scant regard for cost and endurance—has removed it so far from everyday motoring as to leave little scope for transferring technology from the exotic to the mundane. That, though, may be about to change. It now seems that the same technologies which make racing cars go ever faster—the endless pursuit of stiffness, lightness and greater power from smaller engines—are precisely the ones that will be needed more and more to reduce carbon footprints and dependence on oil.

Last year, Formula One's rules were changed to allow racing cars to recover some of their braking energy that is normally lost as heat and use it to boost their speed for overtaking. The kinetic energy recovery system (KERS) that most teams adopted was a battery-based arrangement similar to the regenerative braking found in the Prius and other electric vehicles (see “Boost for Formula One”). But not all the F1 teams chose the Prius approach. Two KERS devices developed in Britain rely on storing the braking energy in rapidly spinning flywheels instead of chemical batteries.

One, made by Flybrid Systems of Northamptonshire in conjunction with transmission specialists Xtrac and Torotrak, is a pure mechanical system that uses a rotor spinning in a vacuum at 60,000 revolutions a minute. It is especially compact, weighing less than 18kg and is no bigger (in plan view) than a sheet of copier paper. The other, developed by Williams Hybrid Power in Oxfordshire for the Williams F1 team, uses technology licensed from Urenco, an Anglo-Dutch-German enterprise that enriches nuclear fuel for power stations. The Urenco process relies on ultra-centrifuges spinning in a vacuum at speeds of over 100,000 revolutions a minute to separate the lighter, fissile isotope of uranium, 235U, from the slightly heavier 238U.

In a recent endurance race, a Porsche 911 GT3 R hybrid racing car that used a Williams flywheel system capable of boosting output at the wheels by an extra 160 horsepower and weighing just 47kg (instead of a battery system two or three times heavier) achieved 25% better fuel economy than conventional versions of the car. Now, Land Rover and Williams are working on a tiny flywheel design that can be mass produced for under $1,500, and used instead of batteries in hybrid family cars.

Besides finding their way into road vehicles, high-momentum flywheel systems are being investigated as ways of storing energy collected from intermittent sources such as wind and solar power, and for responding quickly to increases in demand that are now dealt with by switching on stand-by generators fuelled by natural gas. Beacon Power, a firm based in Massachusetts, is building a 20-megawatt plant in Stephentown, New York, that uses 200 flywheels to stabilise the local grid in this way.

Back on the road, flywheel hybrids that cut both fuel consumption and greenhouse-gas emissions by 30% or more appear to be only three or four years away. When they arrive, today's coal-fired electric cars will look decidedly dirty by comparison. Roll on the day.

(Formula One photo through a Creative Commons licence from Jake Archibald on Flickr)

Currently, electric cars, with their finicky technology, trendy greenness, and massive tax subsidies, are the 21st century equivalent of Jimmy Carter's rooftop solar collectors of the 1970s. They only make sense because of market-distorting tax treatment and the prestige value of making the owner seem greener. Like the rooftop solar collectors, they are likely to be stop being popular once the subsidies are gone, and they are likely to all be junked shortly thereafter.

If the direct money costs weren't being distorted enough, an honest accounting for their "greenness" would look even worse. Come up with an honest environmental footprint for them, starting with the mining of Bolivian lithium and Chinese rare earths, to the ultimate source of the electric power, and they look decidedly less green. Factor in the unavoidable need to replace a very expensive and resource-intensive battery pack and the inherent obsolescence of all fancy consumer electronics, and very few electric cars will ever have their batteries replace. Most will be junked at that point.

The main reason for this folly is a Utopian desire for the ideological purity of a "zero emission vehicle", even if that means that the emissions are merely hidden in distant mines, smelters, and power plants. If the real goal was to reduce air pollution and fuel consumption, we'd be much better off defining some sort of ultra-low emission vehicle whose specifications could be met by a very light vehicle with a state of the art high efficiency, low-emission diesel engine. The laws of thermodynamics insist that a diesel engine will always have much better efficiency than an Otto (spark-ignition) engine, and the laws of chemistry allow it to be designed to run on a wider range of fuels. Even in the pre-computer days, the German "hypercycle" diesel engine would run on any combination of gasoline, kerosene, diesel oil, jet fuel, vegetable oil, or alcohol, and would run with a fair proportion of waste lube oil mixed into the fuel. The patents are all in the public domain, and with modern computer control, the design could be optimized even more.

A non-electric vehicle would be cheaper to produce, would not require expensive batteries made of rare materials, would have more payload capacity since it wouldn't need to waste fuel and space schlepping batteries around (although the diesel engine itself would likely be heavier than a permanent magnet electric motor of similar power), and would probably have double the average service life on the road since battery replacement wouldn't loom as the point for a "replace or scrap" decision by the owners. With all these advantages in favor of small, light, simple diesel vehicles, many more people would buy them than would by the electrics, resulting in lower net emissions averaged over an entire city compared to a city with nearly all the vehicles being of conventional design mixed with a very few "zero-emission" vehicles. When the global ecosystem is included in the calculations, the light-diesel system would definitely come out ahead.

So-called "zero-emission" vehicles are a prime example of where perfect is the enemy of good, in terms of total net environmental benefit.

The hostility of these American commenters to electric cars is disappointing but not surprising.

Here in Europe we have different circumstances (shorter commutes, limited need for air-con, denser cities) and are less tolerant of smog, vehicle noise and pollution: to which I guess Californian residents have become inured.

From a European's point of view, if you look beyond the mis-information (usually promulgated by vested interests) you will realise that non-fossil fuel vehicles (mainly electric) will transform the ambiance of our cities within 10 years. Yes, there will necessarily remain a percentage of vehicles spewing fumes and noise, but I see 90% being electrically powered. It will be the biggest improvement in quality of life within our cities since the Clean Air Acts.
.
.
Simply put, electric vehicles (battery, not hybrid) have two life-changing advantages:

first, they will transform the environment within city and town centres as dramatically as did the end of horse-drawn traffic last century (ended thousands of tons of horse shit on the streets every day);

second, they will liberate European car owners. Motoring becomes (apparently) free. The marginal cost of extra journeys appears to be zero. No more £90 a time visits to a petrol station. No more mechanical servicing bills. Just change the batteries each ten years. A car as easy to own as a hoover.

Sure, the monthly debits for the annual household electric bill will be a lot higher, but this is as remote and removed as the credit card instalments are to people's shopping purchases. And probably paid by the head of the household anyway.
.
.
Sure, overall pollution is only reduced - not eliminated. But it is also relocated from (very inefficient) internal combustion engines milling around en masse to (efficient) electricity-generating power stations remoter from centres of population.
.
These factors may be of less interest to the US - the land of super-cheap petrol, greater distances, temperature extremes, vested interests (plus a macho car culture). That's fine. Drive your lower-pollution diesels and such (if you can get US car companies to ditch their profitable gas-guzzlers to make them).

But the US is only 5% of the world's population, so please don't generalise for the rest of us. China, for example, is powering ahead as the world-leader in electric bikes & motorbikes - Barcelona (amongst others) finds these ideal for commuting.

1 - D. Sherman is quite right - modern diesels are better than electric hybrids under many conditions of actual use and likely to get better still. And they can burn anything, including petrol (& coal/water), if the high-pressure fuel pump is designed correctly, possibly with ceramic components. This is not magic - higher compression ratios make all ICEs more efficient for fundamental physics reasons - which is also why all sports engines are high compression. Getting US users to switch to diesel, as most European drivers have now done, would reduce Carbon emissions completely without pain for drivers - diesel cars are every bit as good as Gas ones. US prejudices on this need addressing, as do concerns about increased NOx emissions (from the high temperature that goes with the greater efficiency).

2 - Flywheels for energy storage are very well known and have been worked on for years, with steady improvements. There may be some safety concerns. In any case the optimum solution for mobile lightweight energy storage is already very well known. It is chemical storage with the heaviest component (Oxygen) not carried in the vehicle. Sounds familiar? It is called an internal combustion engine.

After a horrendous commute, I moved close to work and sold my car. Remember: the house with the yard and the two-car garage takes up the whole weekend in maintenance. We should look into better building materials for nicer apartment complexes... seems like better potential return on investment than this stuff.

Babbage, you should follow the research at Carnegie Mellon on an all-electric city commuting car using lead-acid batteries, regenerative braking, and an appropriately-sized supercapacitor instead of a flywheel. (MIT is also working on redesigning lithium battery electrodes to make them ultracapacitors.) The CMU researchers analyze GPS tracking data from volunteers to come up with custom designed configurations appropriate for everyday use instead of the worst case, using new software and current technology. Further, federal and state subsidies might not be needed, but instead some liberalization of the current heavy restrictions on building and modifying autos that still assumes Fordism is the only way. Lowering speed limits to 35 mph would make it possible for Neighborhood Electric Vehicles to be constructed locally to fit local requirements, often by modifying gas cars. These cars need not be personally owned, but could be, like Zipcars, rented or leased, and then could be made part of a regional transportation plan with diesel-electric bus rapid transit, improved from the Las Vegas example. Finally, recharging might well be placed not at home with home-owner-financed solar panels or wind turbines, but instead at work or while shopping at Walmart from more efficient solar, or, better, nuclear, such as tiny thorium reactors. Instead of designing electric vehicles to imitate and replace suburban gas vehicles, we ought to think about designing a whole new system that is more flexible and intelligent, just as modern computers balance memory, cache, and storage, and can have specialized uses and designs, all using common technology that is incrementally improved instead of waiting for gee-whiz disruptive inventions such as your flywheels.

In an auto accident, the petrol tank typically does not (contra Hollywood) explode or even burst into flames. The obvious question is: what happens if the flywheel box is damaged? Or even just springs a small leak -- since loss of vacuum would lead to turbulence which would destroy the box as well.

Are there any details available on how the companies address that issue?

As a fellow Angeleno (part time), I sympathize. I'd also worry about traffic. If the Leaf isn't air conditioned, hours of sitting still in LA's notorious jams sweltering in the summer heat would quickly take the bloom of that rose. If the car has AC, then running it for very long would eat deeply into your range. Getting home vs. avoiding heat stroke isn't a trade off the car should force on you.

And of course if you run out of juice in a jam, not only will you swelter without relief, but that tow truck will be a very long time coming. Better pack some emergency rations, and a good pair of shoes.

I'm pretty sure that Harry Harrison's Stainless Steel Rat was driving around on a (stolen) police bike using a flywheel for energy storage: at least 2 decades ago. Anyone else remember which book it was?

We have made a little progress with the acknowledging description,"coal fired electric cars."

Next problem: Flywheels. Nope, they are not going to get there, probably ever. It actually costs quite a lot to build a heavy wheel that spins fast enough to do much energy storage. Efficiency of the coupling apparatus, whether mechanical or electrical, into and out of that device is a little problem also.

Good observation: Lithium batteries require a lot of cooling. In spite of the near absolute secrecy about efficiency of charging and discharging lithium batteries, here we have a clue leaking out. Yes, heat means something is lost in the process of storing electric energy. Not such a big surprise, but try to find out real numbers for batteries and the difficulty getting honest answers is the only thing we should be surprised about.

The weight of the Prius batteries, and the adequacy of their capacity seem to have been a well engineered balance. Depending on the efficiency of the electric system, the weight does not matter much, since energy of acceleration comes back and energy for hill climing comes back.

Weight then only impacts rolling resistance. Toyota actually worked hard on this rolling resistance with their choice of tires, though they seem to have backed off a little from the initial Bridgestones with Crr of .007. Their synergy drive then circumvented the electrical inefficiencies rather skillfully.

And then along comes the plug-in idiocy.

My idiocy is to believe that the fashion conscious car driving public can be induced to rethink the kind of vehicle they drive in, such that a serious reduction in energy use can be achieved. Yes, there is a need to change the shape of cars. And no, they can no longer be the customary and comfortable past expressions of male sexual prowess of the muscle car, nor the demonstrations of the motherly womb of the SUV.

A glimpse at how things might look can be had at www.miastrada.com where only the brave should tread. Prepare to be shocked, horrified, and disgusted.

Sophisticated hydraulic transmissions (see www.artemisip.com/appli_auto_transm.htm) permit the IC engine to run at optimal speed and power and store braking energy in accumulators, which are rather less hi-tech than flywheels. The converted BMW 530 mentioned in the linked page displays twice the urban mpg of its manual equivalent, and hydraulics is inexpensive compared to electric transmsission.

> [T]he electricity delivered during off-peak periods comes from dirty coal-fired power stations—rather negating the point of having a zero-emission vehicle in the first place.

Depending on where you are, large parts of the base load will come from nuclear power. Since these plants take hours or days to heat up, they're kept on continuously, even during peak time. It's debatable whether loading your battery during peak time is greener.

D.Sherman, Here here!! Though the gasoline IC engine might still surprise. The measured efficiency of the Prius engine is 35% to 38% according to data in Argone National Lab reports. So the simpler catalytic converters that already exist in the USA might keep these in the running, compared to diesels.

willstewart, Here here also!! Though the merits of diesels are important, so are the regenerative braking systems that require some kind of electrical machinery; or the not likely flywheel type of thing that our host has come to be fond of.

guillaume rischard: Ask not from where your EV electricity comes; it comes from coal.

joeschuren: Design away on the new system but keep low speed limits out of it; I value my time. Also keep public transportation out of it: I value my time and my suburban life choices. Ok, for people who want to live and work in neat little clusters, give it to them. Keep the roads a little more open for real folk.

But why not make cars half as wide and double the lanes on the freeway? (See how at the link I previously gave.)

Aaaaah yes, flywheels... my correspondent certainly isnt the first to consider flywheels in hybrid vehicle design. I do recall an article, penned a few years ago, discussing the merits of advanced flywheels in vehicle design, and their potential impacts on vehicle performance and MPG.

The trouble is, all of this discussion is just that, "potential". Flywheels present several mechanical reliability issues. In a Formula One race chassis, a flywheel can be expected to last one race or two - and it can be easily replaced due to unlimited budgets. However, in production, a flywheels operating requirements resemble those of a turbocharger, with intense lubrication requirements, high heat of operation, and the resulting reduced service life. Replacement cost will likely equal that of a turbocharger as well, due to micromachined bearings and vacuum pressurization requirements. Heck, the potential to throw the assembly off-balance in a minor accident may result in a huge market for "OEM flywheel assemblies"...

I believe that several technologies will contribute to the drivetrain of the future - possibly flywheel, but more likely hydraulic and electrical. Eaton has several hydraulic hybrid drivetrains on the road today that do not have the battery weight overhead. In addition, the fluid energy does not decay when the vehicle is stopped - flywheels do not spin forever, even in a vacuum.

I wonder where in Europe you find yourself where folks imagine themselves to be so "less tolerant" of poor air quality than we are in the USA. I found air in Paris far worse than even Los Angeles since the catalytic converter became widely used.

Diesels are mostly not allowed in the USA due to our lower tolerance of the effects of the oxides of Nitrogen which they spew excessively. We look forward to the day that these are fixed, at which point the merits of diesels may prevail over gasoline engines.

But oh dear again, rostbeef, you give me so many juicy, tantalizing openings and I do not have time to shoot at them all.

Check the analysis by Christopher D who seems to be quite capable of analysis relating to energy matters. He could lead us away from the trendy direction set by Tinker Bell Institute of Technology, which seems to be the institute from which most Europeans, UKers and, sorry to say, us Americans as well graduated.

When it comes to vested interests, there is also the sound conservative line of thinking that would suggest that there will never be anything more than nambypamby environmentalism until there are solutions that align sensible environmental goals with vested interests. Nope, Tinkertech does not offer that kind of real engineering skills.

Maybe the Tinkertech faculty was trained in the days when getting the emission source over the hill was a great accomplishment. But since many of these profs came from MIT, where nobody had to actually get a passing grade in physics since about 1970, they did not realize that CO2 made over the hill was as bad as that made in the LA smog basin. That being the present environmental problem, we are in a bad way in the developed world.

I'm just an electrical engineer, but the flywheel concept feels like a reach for another weakly-researched vehicle technology driven by our desperation to bail out of the oil standard. What does a fancy flywheel buy that a fancy capacitor doesn't provide for much less money and safety risk?

We don't see things spinning at 60,000 RPM in everyday life. This is how fast the turbine in the new NATO Joint Strike Fighter will spin to lift the aircraft off the ground. As others have reported, we should probably check the price tag on that before putting one in our cars.

Like PSH, I am not looking forward to facing summer traffic jams with only a flywheel to keep me cool. As a Seattle commuter, being exposed to the elements is out of the question too.

Bottom line, we can probably create individual transportation that greatly reduces or eliminates the need for fossil fuels. But we won't be off the oil standard until trucks, ships, and airplanes can be addressed. Heavy transportation requires too much power for non-fuel-based technologies, and there is little incentive for me to look any further than a Prius for green transportation until they do.

"Moreover, supplies of the metal (lithium) are far from abundant, and are located in countries not necessarily friendly to America: the biggest reserves are in Bolivia, China and Russia."

Incorrect. The biggest reserves are in Chile and Argentina, followed by the three you mentioned and thereafter by the USA, Canada and Australia. Serbia and Namibia also have decent sized deposits, and we have been recently informed that Afghanistan is also prospective. It is quiet a different substance to oil. Its a simple element that can neither be created nor destroyed, unlike oil, which is made up of complex molecules formed under very particular conditions over geological time frames. Once its gone, its gone. Lithium will always be here, the only question is whether it can be economically extracted.

At the moment, its a non-issue, the raw material cost of lithium makes up around 1-2% of the total battery cost.